"I will tell you, there's a real opportunity, there's a real opportunity as we repeal and replace Obamacare to do exactly what the president said on the campaign, and that is block granting Medicaid back to the states."

The block-grant plan involves the federal government giving the states set amounts. Right now, the government's contributions to Medicaid are more open.

As governor of Indiana, Pence set up a plan in which Medicaid customers contributed a small amount to a health savings account each month. Seema Verma, Trump's nominee to run the Centers for Medicare and Medicaid Services, helped Pence create that plan.

The Indiana plan has led to more than 400,000 new enrollees, according to Indiana University professor Kosali Simon. However, she said she was not sure how the plan would work in other states. "It's hard to know because other places have gotten used to having Medicaid without any cost sharing," Simon said, the Hill reports.

Republicans say that block grants limit government spending and gives states more authority over how the money is spent. Democrats say the grants would lead to states being unable to pay for the coverage, then capping enrollment and turning people away.

Gail Wilensky, the head of the Centers for Medicare and Medicaid Services under George H.W. Bush, said that with the current system, states have no incentive to efficiently use the money they have.

She said that another GOP plan for per-capita spending would be preferable to block grants, because that would allow more people to enroll in Medicaid in the event of a downturn. "If you just had a block grant, you could leave the jurisdictions vulnerable to major swings in the economy," Wilensky said.

Democrats have focused on Republicans changing Medicare, the program that focuses on seniors. "I say to my Republican colleagues: Turn back, because we will fight you on this tooth and nail, and we will win," New York Democrat Sen. Chuck Schumer said.

Former White House adviser Gene Sperling said Democrats must shift focus to the GOP's plans for Medicaid instead. In a New York Times opinion piece Sunday, he wrote, "If Donald J. Trump decides to gut the basic guarantee of Medicare and revamp its structure so that it hurts older and sicker people, Democrats must and will push back hard. But if Democrats focus too much of their attention on Medicare, they may inadvertently assist the quieter war on Medicaid — one that could deny health benefits to millions of children, seniors, working families, and people with disabilities."

On Dec. 19, Republican lawmakers, including Utah Sen. Orrin Hatch,sent a letter to President Barack Obama's administration, raising concerns about wasting government money in an Obamacare expansion of Medicaid.